21431142 has 28 divisors (see below), whose sum is σ = 48201300. Its totient is φ = 7143228.

The previous prime is 21431141. The next prime is 21431149. The reversal of 21431142 is 24113412.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21431141) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 13 ways as a sum of consecutive naturals, for example, 5892 + ... + 8807.

It is an arithmetic number, because the mean of its divisors is an integer number (1721475).

Almost surely, 2^21431142 is an apocalyptic number.

21431142 is an abundant number, since it is smaller than the sum of its proper divisors (26770158).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21431142 is an equidigital number, since it uses as much as digits as its factorization.

21431142 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14719 (or 14704 counting only the distinct ones).

The product of its digits is 192, while the sum is 18.

The square root of 21431142 is about 4629.3781439844. The cubic root of 21431142 is about 277.7677182609.

Adding to 21431142 its reverse (24113412), we get a palindrome (45544554).

The spelling of 21431142 in words is "twenty-one million, four hundred thirty-one thousand, one hundred forty-two".